State‐of‐the‐Art Framework for Structural Design of Offshore Wind Jacket Foundations

Nielsen, Martin Bjerre; Jensen, Jørgen Juncher; Harper, Christopher; Knudsen, Lennart Skovbjerg; Pedersen, Ronnie

doi:10.1002/cepa.1139

Cited by 2 publications

(2 citation statements)

References 5 publications

(2 reference statements)

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“…The local joint flexibility representing the effective stiffness of a tubular joint is modelled via the simplified Buitrago equations [30]. This approach is known to be imprecise [32], so to account for this uncertainty, a value of 0.50 is chosen. The soil stiffness is modified via correction parameters, py, tz, qw, which update the initial stiffness of the linearized API curves [29].…”

Section: Physical Parameters To Be Updatedmentioning

confidence: 99%

Data-driven model updating of an offshore wind jacket substructure

Augustyn

Smolka

Tygesen

et al. 2020

Applied Ocean Research

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The present paper provides a model updating application study concerning the jacket substructure of an offshore wind turbine. The updating is resolved in a sensitivity-based parameter estimation setting, where a cost function expressing the discrepancy between experimentally obtained modal parameters and model-predicted ones is minimized. The modal parameters of the physical system are estimated through stochastic subspace identification (SSI) applied to vibration data captured for idling and operational states of the turbine. From a theoretical outset, the identification approach relies on the system being linear and time-invariant (LTI) and the input white noise random processes; criteria which are violated in this application due to sources such as operational variability, the turbine controller, and non-linear damping. Consequently, particular attention is given to assess the feasibility of extracting modal parameters through SSI under the prevailing conditions and subsequently using these parameters for model updating. On this basis, it is deemed necessary to disregard the operational turbine states-which severely promote non-linear and time-variant structural behaviour and, as such, imprecise parameter estimation results-and conduct the model updating based on modal parameters extracted solely from the idling state. The uncertainties associated with the modal parameter estimates and the model parameters to be updated are outlined and included in the updating procedure using weighting matrices in the sensitivity-based formulation. By conducting the model updating based on in-situ data harvested from the jacket substructure during idling conditions, the maximum eigenfrequency deviation between the experimental estimates and the model-predicted ones is reduced from 30% to 1%.

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Section: Physical Parameters To Be Updatedmentioning

confidence: 99%

Data-driven model updating of an offshore wind jacket substructure

Augustyn

Smolka

Tygesen

et al. 2020

Applied Ocean Research

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“…One is the global finite element modeling to analyze from macroscopic scale [ 6 , 7 ]. The joints of global model are established using beam elements, ignoring the influence of nodal effects, such as the flexibility, geometry and weld configuration of its substructure joints [ 8 , 9 ]. The other is local modeling via small-scale analysis, and the local joint flexibilities of tubular K/DK-joints [ 10 , 11 ], T/Y-joints [ 12 , 13 , 14 ], or X-joints [ 15 , 16 ] are established individually using solid or shell elements for analysis.…”

Section: Introductionmentioning

confidence: 99%

Multiaxial Fatigue Analysis of Jacket-Type Offshore Wind Turbine Based on Multi-Scale Finite Element Model

Peng

Liu

et al. 2023

Materials

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The fatigue damage of a local joint is the key factor accounting for the structural failure of a jacket-type offshore wind turbine. Meanwhile, the structure experiences a complex multiaxial stress state under wind and wave random loading. This paper aims to develop a multi-scale modeling method for a jacket-type offshore wind turbine, in which local joints of the jacket are modeled in a detail by using solid elements, and other components are modeled via the common beam element. Considering the multiaxial stress state of the local joint, multi-axial fatigue damage analysis based on the multiaxial S–N curve is performed using equivalent Mises and Lemaitre methods. The uniaxial fatigue damage data of the jacket model calculated using the multi-scale finite element model are compared with those of the conventional beam model. The results show that the tubular joint of jacket leg and brace connections can be modeled using the multi-scale method, since the uniaxial fatigue damage degree can reach a 15% difference. The comparison of uniaxial and multiaxial fatigue results obtained using the multi-scale finite element model shows that the difference can be about 15% larger. It is suggested that the multi-scale finite element model should be used for better accuracy in the multiaxial fatigue analysis of the jacket-type offshore wind turbine under wind and wave random loading.

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State‐of‐the‐Art Framework for Structural Design of Offshore Wind Jacket Foundations

Cited by 2 publications

References 5 publications

Data-driven model updating of an offshore wind jacket substructure

Data-driven model updating of an offshore wind jacket substructure

Multiaxial Fatigue Analysis of Jacket-Type Offshore Wind Turbine Based on Multi-Scale Finite Element Model

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